How can a node be an array of objects? Does the node accepts multiple values or something? It might help if you can share a sample request. In a hind sight, groovy might be your best bet. It is indeed very similar to Java. Here are the links to two api's which might help you get started:
soapui api:
http://www.soapui.org/apidocs/groovy api:
http://groovy.codehaus.org/api/index.htmlI would also suggest the link below to get you started just to give you some basics on arrays in groovy.
http://pleac.sourceforge.net/pleac_groovy/arrays.htmlHope this helps.
Regards,
Deepesh Jain.